Does owning a gun change your behavior?

Atmosphere at the memorial service for country singer Mindy McCready in Nashville, Tenn. McCready was found dead from an apparent suicide in early 2013. See more firearms pictures.

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In the wake of any gun-related tragedy, one of the big questions that always arises is: Would this have happened if the person hadn't had a gun? Would country singer Mindy McCready still have killed her dog and then herself? Would Olympian Oscar Pistorius have shot his girlfriend? We obviously can't go back in time and see how these situations would have played out sans firearms, but we can look at the research into how gun ownership affects human behavior.

Pro-gun advocates often say they own guns for sport -- hunting and target practice -- or as protection from criminals [source: Bushman]. They say that gun ownership is higher than ever in the U.S., and not coincidentally, the murder rate has fallen 49 percent since 1991 [source: National Rifle Association].

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Pro-gun control advocates argue that fewer available guns would equal less death and that other weapons like knives -- while still dangerous – don't kill as many people as guns do [source: Anderson]. The 2012 General Social Survey says that household gun ownership has hit a 35-year low, coming in at just 34 percent compared with 43 percent in the 1990s, which would counteract the correlation between ownership and a decreased crime rate [source: Tavernise and Gebeloff]. The discrepancy between the two reports is probably because while fewer U.S. households might have guns, the ones that do have more of them than they used to.

The ways that gun ownership impacts behavior are complicated to say the least. But research seems to indicate that owning a gun or even just seeing one does change how people behave.

There's something called the "weapons effect," a phenomenon first studied in 1967. Researchers Leonard Berkowitz and Anthony LePage found that just the presence of firearms in a room made people take more aggressive actions, administering stronger electric shocks to other study participants. A 1975 study showed that a person drove more aggressively when behind a truck with a gun in a rack than one with no gun – even though logic might caution you about honking your horn at a truck displaying a weapon. People have an evolutionary propensity to identify dangerous items very quickly – and studies show people can identify guns as quickly as snakes. It seems as if weapons trigger the same part of our brain as danger and aggression [source: Bushman]. Another 2006 study showed that gun interaction increased testosterone levels and aggressive behavior in men [source: Klinesmith].

Guns and Suicide

When you think of gun violence, you might picture a criminal wielding a 9 mm pistol at an unsuspecting victim or a homeowner using a shotgun to defend himself from an intruder, but the majority of gun deaths in the U.S. aren't from assaults but people using guns to take their own lives [source: Sapien]. In 2011, the most recent statistical year available, 19,766 people in the U.S. committed suicide with a firearm. Meanwhile, 11,101 committed homicide with a firearm [source: Hoyert and Xu].

In Mindy McCready's case, it's pretty easy to argue that without a gun she might have found some other way to take her life. Police also found bottles of prescription medications in her home [source: People Magazine].

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But there is a connection between owning a gun and taking one's own life. A Centers for Disease Control and Prevention (CDC) 2004 survey of gun violence research published in the American Journal of Epidemiology found that gun owners who committed suicide were more likely to use their guns rather than other methods, like pills. A 1992 study cited in the CDC survey discovered that people with a gun in the home were five times more likely to commit suicide overall. And a large-scale, national 2003 study found that access to a gun made a person more than three times more likely to commit suicide than someone without firearms [source: Dahlberg, Ikeda and Kresnow].

Why would that be? Experts posit that suicide is often an impulsive act, occurring when a person is suffering an acute crisis. Eighty-five to 90 percent of people who shoot themselves succeed in dying, a much higher rate than with any other method of suicide. Arguably, if people did not have access to guns during that extreme period in their lives, it is likely they'd still be alive. In fact, the Israeli Defense Force found it lowered the suicide rate 40 percent among its soldiers simply by forbidding them from taking their weapons home over the weekend [source: Neyfakh].

Guns and Homicide

A graphic illustrating the six weapons Oscar Pistorius had applied to own firearms licenses for. The Olympian was charged with the murder of his girlfriend Reeva Steenkamp who was shot and killed in his apartment in Pretoria, South Africa.

Rudi Louw/Graphics24/Gallo Images/Getty Images

It's pretty clear that owning a gun puts you at higher risk for harming yourself, but what about harming others?

A lot of the government-funded research on gun violence comes from the early to mid-1990s. That's because in 1996, the National Rifle Association successfully lobbied Congress to cut funding for gun violence studies. But before that, the CDC found that having a gun in the home made homicide about three times more likely for family members in that house [source: Sapien]. This jibes with a 1992 study, which found that family disputes that turned violent were three times more likely to result in death when a firearm was present versus other weapons [source: Saltzman].

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Most homicides aren't carefully planned events. Instead, an argument with a friend or family member -- maybe over money or infidelity -- turns violent. Add a gun to the mix and the chances of death are greater than say, using a baseball or a knife.

But researchers point out that the correlation between homicide and firearms in the house is not as strong as the relationship between suicide and firearms in the house. Most murder victims are not shot at home – unless they are women, children or elderly. Also households with gun ownership might be more engaged in criminal activity. But one often-cited study of 400 homicide victims who were killed in their homes showed that half died of gunshot wounds and in the vast majority of cases, they knew the perpetrator. Forced entry was rare – only 14 percent of the time. Thirty-six percent of these homes owned firearms versus 23 percent of control households [source: Hemenway].

The change in behavior extends to the street. A 2009 study looked at 677 shootings in Philadelphia over two-and-a-half years and found that people who carried guns were 4.5 times more likely to be shot and 4.2 times more likely to be killed as unarmed people. The study authors think that guns may give their owners a sense of empowerment that leads them to act rashly or go into dangerous situations or places they might otherwise avoid [sources: Callaway,Branas].

Guns and Perception

Not only does owning a gun change your behavior, but it also can change how people perceive you. A study of more than 600 people found that participants viewed images of gun-toting men as stronger and more powerful than men holding other objects like a power drill [source: Nicholson].

Author's Note: Does owning a gun change your behavior?

In the fall of 2011 I was sitting on the couch watching TV when I thought I heard someone fall off of our roof. There was a loud bang right outside followed by a man screaming. It was a teen shooting my neighbor across the street in the leg during a botched robbery attempt.

As you'd expect, that incident shook up everyone on our block. Any time I came home after dark I was afraid for my safety, and I definitely thought about arming myself. The thing that stopped me from getting a gun was realizing that in a similar situation, I didn't think I'd be able to use it.

The bullet didn't cause any major damage to my neighbor's leg, and he was up and about again within a few weeks. As soon as he was on the mend, he did get a handgun to protect himself and his wife.

I've always gone back and forth on gun ownership. While I don't think that owning a gun is for me, I can see wanting to protect yourself. Between my neighbor's shooting and getting mugged on our street a few years before that, I definitely know what it's like to feel unsafe in your home and want to empower yourself somehow.

Dahlberg, Linda L. "Guns in the Home and Risk of a Violent Death in the Home: Findings from a National Study." American Journal of Epidemiology. Volume 160, Issue 10. Pp. 929-936. Nov. 15, 2004. (Feb. 25, 2013) http://aje.oxfordjournals.org/content/160/10/929.full

Harvard School of Public Health. "Firearm Access is a Risk Factor for Suicide." (Feb. 25, 2013) http://www.hsph.harvard.edu/means-matter/means-matter/risk/

Hemenway, David, Ph.D. "Risks and Benefits of a Gun in the Home." American Journal of Lifestyle Medicine. 2011. (Feb. 27, 2013) http://www.comedsoc.org/images/Risk%20Guns%20at%20Home%20Hemenway%20Am%20J%20Lifestyle%20Med%206-12_copy1.pdf

Saltzman, LE. "Weapon involvement and injury outcomes in family and intimate assaults." The Journal of the American Medical Association. June 10, 1992. (Feb. 27, 2013) http://www.ncbi.nlm.nih.gov/pubmed/1588718